monoflow tee from basement to second floor: get rid of monoflow tee

iexpl

basement mainloop schematics (not to the scale). The bathroom 2 monoflow T is only 6" apart! And kitchen monoflow T is right next to the bathroom monoflow T. Also, kitchen side loop did not use only copper pipe, it used some old PEX (black) pipe. Both kitchen and bathroom has issues with very little heat provided, e.g. lukewarm baseboard.

here are some photos:
basement mainloop schematics (not to the scale)


bathroom side loop with a copper pipe connected to the black PEX pipe. Is this strange?

iexpl

Now, the gauges while boiler is not called for heat. The pressure gauge is about ~10 feet, and temperature is 130F. The boiler's max temperature is set at 190F. Another boiler for unit 1 that is also not called for heat, the pressure gauge is register ~12 psi and temperature is 80F. So, how come the boiler can not maintain a steady pressure?
Another question: what is the big red arrow pointing to the pressure gauge mean? Max pressure for the system, which is at 38 psi?

iexpl

@EdTheHeaterMan to answer your question:
1. Do you believe that the baseboard radiators were the original radiators when the system was installed?
No. The house is 1900. So, it highly likely has steam heat and later converted to the current system. There is one cast iron radiator in the front hall way.

2. Do you see any evidence that the original radiators were 36” wide x 24” tall convectors that were replaced by baseboards?
No idea.

3. Was the system balanced at any time during the time you were there?
No. I did not know this system needs to be balanced. The plumber came to bleeded the system with a pump. Also, he advised me to keep the thermostat at 68 degrees always, and do not adjust the thermostat often.

4. If yes, when did it change?
The problem occurred in the first winter, and get a little better in 2nd winter when the thermostat is kept at 68 degrees always. But 3rd winter (this year), it seems to get some uneven heating. However, the tenants furniture/bed has blocked baseboard as well.

EdTheHeaterMan

This is interesting. I am thinking that the original system was ALL cast Iron radiators or perhaps cast iron convectors in a cabinet to verify this you would need to look at where the pipes in the floor come from. Do the pipes come up near the window then take a turn to the end of the baseboard? look for something like this.
Notice how the pipes may have originally connected to a 36" wide radiator or convector near a window. At some point in time the apartment was renovated and the baseboards were added to the original pipes. (Note the Red arrows)

If that is the case, that would explain the imbalance. The new radiator design may not conform to the original pressure drop designed into the original convector system. To fix this, you would be better off connecting all the baseboards in a series loop.


But you can't do the connections in the basement. You need to do the connections on the second floor.

iexpl

@EdTheHeaterMan connecting all the baseboard in a series loop is very difficult to do due to front and back stairwells. Can I just have a series loop for all the bedrooms on oneside (easy to do), and keep the original system for the Living room , bathroom, and kitchen? And increase the pressure of the boiler for the unit.

Basically, 2 zones. 1 zone for living room, bathroom, kitchen using the existing system.
1 zone for 3 bedrooms (2 bedrooms are already connected)

EdTheHeaterMan

That will work. Two separate thermostats is also the best way to do that. Then you would need 2 circulator pumps or one circulator pump and 2 zone valves. In your situation I would use one valves. I like the Caleffi Z One series 1" valve for the zone that will remain MonoFlo® and the Caleffi Z One series 3/4" for the series loop.

This is because one thermostat will not offer the proper control over the two different types of systems. And I believe you want to fix the imbalance problem, Right?

iexpl

Thanks for the detailed answer @EdTheHeaterMan . I will have to check if the piping was for the original 36" radiators.


1. what happens if I turn the radiator in the front hallway off. Does it help the even heating with the existing monoflo system?

2. what is the best plan of attack assuming the piping is for 36" radiators originally? I can not really see where the pipe come up from under the floor. All I see is that the pipe connected directly to the baseboard like a modern house.
2.1 try to turn off the radiator in the front hallway
2.2 increase the pressure of the boiler to at least 12, maybe 15 psi (given the distance between the boiler to the 2nd floor baseboard are 18'3")
2.3 repiping if the above 2 failed.

Is the above plan right or I missed something (since I am a novice here).



Here are 2 photos for the radiator in the hall way ( 27" long x 25" high x 6" wide). There is a valve in the bottom said open/close.




Full view of the radiator:

iexpl

From @EdTheHeaterMan : "If that is the case, that would explain the imbalance. The new radiator design may not conform to the original pressure drop designed into the original convector system. To fix this, you would be better off connecting all the baseboards in a series loop. "

The pipe did run roughly straight up mostly. *none* is running with a tiny spacing between the supply and return montoflo T except bathroom. And majority of side loops are run at length except kitchen.

However, the 3/4" side loop pipe did run with some turns. The mainloop is about 2-3 feet from the basement wall, so there are some turns of the riser loops to get to the wall of the house.

With these info, and the fact the radiator is the first risers closest to the supply line, does the following plan make sense? Any suggestions?

1. what happens if I turn the radiator in the front hallway off. Does it help the even heating with the existing monoflo system?

2. what is the best plan of attack assuming the piping is for 36" radiators originally? I can not really see where the pipe come up from under the floor. All I see is that the pipe connected directly to the baseboard like a modern house.
2.1 try to turn off the radiator in the front hallway
2.2 increase the pressure of the boiler to at least 12, maybe 15 psi (given the distance between the boiler to the 2nd floor baseboard are 18'3")
2.3 repiping if the above 2 failed.

EdTheHeaterMan

Ok I understand that you have baseboard radiators and the elbow turns down and goes directly into the floor. If I was renovating the home without replacing the floor boards, I would remove the wall convector and remove a small section of the floor in order to direct the piping closer to the wall under the baseboard cover. Or you may have recessed wall convectors placing the ¾” riser close to the wall. Then I would use an elbow to direct ¾” copper to the beginning of the radiator, and do the same at the other end of the baseboard radiator. Like this "When a normal loop cant be run".

Since you do not have that visible pipe under the baseboard radiators, there is a definite possibility that the baseboards are original. You can double check that in the basement. Look where the risers connect to the 1” main. If the supply and the return are close to each other, then you had convectors. If they are far apart then the baseboard was original.

hot_rod

Mustangman said:

Knowing the boiler prssure is critical. Piping doesn't matter if you aren't running enough pressure to reach the second floor. The gauge says 20 psi @ 180? Is that correct?
This post got long and TRVs were mentioned. Are you using TRVs? They can't be used on a Mono flo system. Here is why. In your main, you may have we will say, 6 gpm. Then you hit your first mono flow tee. By design, this tee is going to divert 1 gpm up to your radiatiion take 1 gpm out of the main so between the tees, you have 5 gpm. The theory is, once you hit that return side tee... you will be back to 6 gpm and off to the next tee. If you have a TRV that is closed, you are basically dead heading the mono flow tee against the TRV, and preventing that 1 gpm to get back to your 6 gpm main. There would also be turbulance at the diverter tee which will hinder flow. Imagine the mess if you had 3 TRVs off. You would never balance it. I don't know if this is what you have going on or not.
Good Luck

I’m not sure your TRV explanation makes sense. If a TRV is closed in your example, 6 gpm continues through the tee, “what goes into a tee must come out of a tee”, an old Holohan parable🤭
In some cases with radiators the rads below the piping may not need the diverter tee due to the density difference in the water driving flow. Explained here.

https://www.pmmag.com/articles/84791-diversionary-tactics

Then the Holohan story of the homemade diverter tee created by crushing the copper tube between to tees with a vice grip😂

iexpl

@EdTheHeaterMan Thanks for the repiping suggestions. Given that the boiler pressure is so low, I will focus to fix the basic problem first.

iexpl

@EdTheHeaterMan , can you explain why I can not convert to the series loop in the basement? That is preceisely what the plumber sked me to do. The distance from the basement to 2nd floor distance of ~18ft, there will be about 230 - 260 ft of piping.

I see what issue is the end of loop will not be heated well. Anything other issues?

EdTheHeaterMan

A ¾” 90° elbow has an equivalent length of 2 feet. When using the rule of thumb for selecting the pump head (the friction force the pump needs to pump against) so in the diagram I show here has a total equivalent length of over 350 feet.
62 feet for 31 elbows +190 feet for 10 risers at 19 feet+100 feet for a 20 x30 perimeter = 352 feet. And that does not count the additional run of pipes that may double back from the floor to the end of the radiator. So, you may have over 400 feet of total equivalent pipe length. That may need a stronger circulator pump in some cases. But the amount of heat lost in the vertical pipes inside the wall is also significant.

It may work but you may find that the balance you are trying to achieve will be lost on the unusually long pipe run. The last radiator on the loop will have a lower temperature than the first radiator. That. may be a different imbalance issue after spending all the money to fix the problem.

It may work out just fine. I just don't want to guarantee it if I'm doing the job. You have a legitimate claim "I just spent all that $$$ and it is still out of balance?"

Ask these Questions...

Are there any baseboards that can be connected from end to end without going to the basement?
Can you be sure to put the cast iron radiator as the last radiator in the loop?

If you can eliminate at least 4 of the risers than you will be better off.

iexpl

@EdTheHeaterMan , for a series + monoflo-Tee loop, what happens if I put the radiator (via the existing monoflo Tee) as the first heating element, then the rest of the system is connected via series loop (up and down 3 times)? Seems to me it should work, but I want to check with the Master. Thank you so much! See my proposed design here: https://forum.heatinghelp.com/discussion/comment/1799655#Comment_1799655

EdTheHeaterMan

iexpl said:

@EdTheHeaterMan , for a series + monoflo-Tee loop, what happens if I put the radiator (via the existing monoflo Tee) as the first heating element, then the rest of the system is connected via series loop (up and down 3 times)? Seems to me it should work, but I want to check with the Master. Thank you so much! See my proposed design here: https://forum.heatinghelp.com/discussion/comment/1799655#Comment_1799655

I see that you have a small system so you may not need to have a larger circulator pump, A Taco 007 or whatever is already on your boiler should do fine. Adding 2 zone valves and separating the bedrooms from the Living/Kitchen side will work great. The bedroom zone can be piped as I suggested, I can see why you can't do the living/bath/kitchen because there is no easy way to get the pipe past the bathtub. Sliding a 3/4" PEX through the bathroom wall inside the kitchen cabinet and behind the refrigerator is not the easiest thing to do either. Since that zone is also very small, I believe it will work as I illustrate in this diagram.

Do not put the cast iron radiator at the beginning of the loop. Place it on a separate home run to the boiler room. Depending on how the plumber connects that CI Rad it will get warm when either thermostat calls for heat, or you can connect it to a zone so only one thermostat operates it. See the illustration

iexpl

For the existing monoflo Tee system, I just turned off the front hall radiator (a knob on the radiator itself). Based on what I am reading, this will disturb the balance of the existing system and may cause other rooms (e.g. second floor unit) not getting heat. Am I read? Basically, I need to leave the radiator as is (in the fully opened state) to keep the system in the old balance.

I am worried about this seemingly harmful turn off of the radiator.